A Consumer Advocate Decided to Investigate the Average Wait Time

Multiple Choice

A consumer advocate decided to investigate the average wait time for a table for one at two local restaurants. Eighteen customers were sent to each restaurant at the same randomly selected times and the time they waited for a table was recorded in minutes. The following sample data was obtained.
$\begin{array}{|l|l|l|l|l|l|l|l|l|l|l|l|l|l|l|l|l|l|l|}\hline \text { A } & 10 & 15 & 7 & 9 & 20 & 5 & 15 & 5 & 7 & 0 & 10 & 12 & 19 & 6 & 0 & 5 & 22 & 18 \\\hline \text { B } & 12 & 17 & 5 & 12 & 8 & 2 & 10 & 25 & 6 & 35 & 10 & 14 & 9 & 22 & 20 & 18 & 5 & 13 \\\hline\end{array}$

Find a $90 \%$ confidence interval for the difference, $\mu _ { A } - \mu _ { B }$ , between the mean wait time for restaurant $\mathrm { A }$ and the mean wait time for restaurant $\mathrm { B }$ .

A) $( 10.28,13.5 )$
B) $( - 7.45 , - 1 )$
C) $( - 1,7.45 )$
D) $( - 7.45,1 )$
E) $( - 13.5 , - 10.28 )$